The continued increase in popularity of roller skates has resulted in an increased demand for greater performance from the skates. To achieve greater performance from the roller skate, skate designers and manufacturers continue to search for designs and manufacturing techniques to improve the handling, maneuverability, support, and durability the skate can offer the user.
Conventionally, prior art roller skates have been manufactured by first fabricating a shoe or boot to secure to the foot of the user, and secondly by attaching wheels to the shoe or boot through the use of a wheel hanger or truck assembly. The truck assembly is normally attached to the shoe or boot using screws, bolts, rivets or another similar form of fastener. For example, U.S. Pat. No. 4,262,918 issued to Sandino discloses a roller skate chassis including a foot plate unitarily molded with wheel trucks and wheel axle mounts. The footplate is then attached to a shoe member by threaded screws or rivets. As a result of this two piece construction, the large amount of internal stresses developed in the skate during use are concentrated at the junction between the shoe member or boot and the foot plate or truck assembly. This concentration of stress can lead to gradual separation of the boot from the plate resulting in excessive play or movement between the parts reducing the handling and maneuverability of the skate. Also, the fasteners may fail or rupture causing complete separation and possible injury to the user. Most importantly, because of the practical inability of fasteners to adequately join two separate, non-homogenous parts together as a single integral unit, the lines of force transmitted through the boot during use are not sufficiently distributed throughout the skate to maximize the handling and maneuverability characteristics of the particular skate. Lastly, the manufacturing of the skate disclosed in the Sandino patent necessarily includes a separate additional step of attaching the shoe member to the foot plate.
U.S. Pat. No. 4,295,655 issued to Landay et al. discloses a roller skate including an upper boot adhesively bonded by injection molding to a beam sole or foot plate to which is attached wheel hanger structures. In this design, the internal stress in the skate will be concentrated at the junction between the beam sole and the hanger structures because of the inability of these connections to evenly distribute the lines of force created in the skate. The adhesive connection between the upper boot and the beam sole will be more apt to provide an even force distribution throughout the skate than a connection formed by other fastening techniques. However, since the upper boot is constructed of a different material than the beam sole, the connection is not as effective as a homogeneous, integrally molded junction in distributing forces while minimizing junction stresses. Moreover, the manufacturing process of the skate disclosed in Landay et al. would necessarily involve the steps of attaching both the upper boot and the hanger structures to the beam sole.
The handling and maneuverability of wheeled devices has been improved by the use of a truck assembly having a deflection beam extending at an angle from an upper support plate to form an axle hub for supporting the wheels. As disclosed in U.S. Pat. No. 4,398,735 to Evans et al., the deflection beam, combined with a impact post for creating a pivot point for rotation of the axle hub, provides a very stable support system with minimal wobble at high speeds and a high degree of maneuverability. However, since the deflection beam is fastened to an upper board, a high concentration of stress will be developed in the junction between the beam and the board causing an uneven distribution of forces in the truck assembly. Also, pivoted lateral movement of a user's foot, ankle and leg is not effectively transmitted to the truck assembly since no shoe or boot is attached to the upper board. Consequently, the maneuverability and handling potential of the skate is not maximized and the benefits obtained by the deflection beam can not be fully appreciated.